Anesthesia and analgesia
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Anesthesia and analgesia · Sep 2005
Antiemetics of the 5-hydroxytryptamine 3A antagonist class inhibit muscle nicotinic acetylcholine receptors.
Antagonists of the serotonergic 5-hydroxytryptamine 3A receptor (5-HT(3A)R) and muscle nicotinic acetylcholine receptors (nAChR) are widely used in anesthesia practice. Both 5-HT(3A)R and nAChR are ligand-gated ion channels with known pharmacological overlap between some of their agonists and antagonists. We studied the actions of clinically used 5-HT(3A)R antagonist antiemetics and nondepolarizing muscle blockers on ionic currents elicited by the activation of mammalian 5-HT(3A)R and muscle nAChR, expressed in Xenopus laevis oocytes. ⋯ Conversely, ondansetron, dolasetron, and granisetron also reversibly inhibited nAChR currents in a dose-dependent manner with IC(50)s of 14.2, 7.8, and 4.4 microM for the adult nAChR and 16.0, 18.6, and 13.9 microM for the embryonic nAChR. Again, hydrodolasetron showed significantly (10 times) more inhibitory potency on the adult nAChR than the parent compound dolasetron. These results indicate that drugs that target specific ligand-gated ion channels may also affect other ion channel types.
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Anesthesia and analgesia · Sep 2005
Sepsis produced by Pseudomonas bacteremia does not alter plasma volume expansion after 0.9% saline infusion in sheep.
Clinicians generally consider sepsis to be a state in which fluid is poorly retained within the vasculature and accumulates within the interstitium. We hypothesized that infusion of 0.9% saline in conscious, chronically instrumented sheep with hyperdynamic bacteremic sepsis would be associated with less plasma volume expansion (PVE) and greater interstitial fluid volume expansion than in conscious, nonseptic sheep. Six conscious adult sheep received an IV infusion of 25 mL/kg of 0.9% saline over 20 min (1.25 mL.kg(-1).min(-1)) in a control nonseptic state and during early and late sepsis (4 and 24 h, respectively, after initiation of a standard infusion of live Pseudomonas aeruginosa). ⋯ Volume kinetic analysis was similar in all three protocols. In both nonseptic and septic sheep, infusion of 0.9% saline resulted in similar peak PVE and resolution of PVE over a 3-h interval and similar kinetic parameters. Contrary to clinical impressions and to our hypothesis, the distribution of 0.9% saline in this animal model was not changed by bacteremia produced by infusion of Pseudomonas aeruginosa.
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Anesthesia and analgesia · Sep 2005
The antinociceptive effect of local or systemic parecoxib combined with lidocaine/clonidine intravenous regional analgesia for complex regional pain syndrome type I in the arm.
We evaluated the efficacy of local or systemic parecoxib combined with lidocaine/clonidine IV regional analgesia in complex regional pain syndrome (CRPS) type 1 in a dominant upper limb. Thirty patients with CRPS type 1 were divided into three groups. The control group (CG) received both IV saline in the healthy limb and IV loco-regional 1 mg/kg of lidocaine + 30 mug of clonidine, diluted to a 10-mL volume with saline. ⋯ The IVRAPG also showed less ketoprofen consumption when comparing the first and second week with the third week (P < 0.05). The VAS score comparison among groups revealed that groups were similar during the first and second week observation, although the IVRAPG showed smaller VAS scores in the third week compared with both CG and SPG (P < 0.05). We conclude the IV 5 mg of parecoxib was an effective antiinflammatory drug combined with clonidine/lidocaine loco-regional block in CRPS type 1.
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Anesthesia and analgesia · Sep 2005
The effects of nebulized salbutamol, external positive end-expiratory pressure, and their combination on respiratory mechanics, hemodynamics, and gas exchange in mechanically ventilated chronic obstructive pulmonary disease patients.
We hypothesized that combined salbutamol and external positive end-expiratory pressure (PEEPe) may present additive benefits in chronic obstructive pulmonary disease (COPD) exacerbation. In 10 anesthetized, mechanically ventilated, and bronchodilator-responsive COPD patients exhibiting moderate intrinsic PEEP (PEEPi), we assessed respiratory system (rs) mechanics, hemodynamics, and gas exchange at (a) baseline (zero PEEPe [ZEEPe]), (b) 30 min after 5 mg of nebulized salbutamol administration (ZEEPe-S), (c) 30 min after setting PEEPe at baseline PEEPi level (PEEPe), and (d) 30 min after 5 mg of nebulized salbutamol administration with PEEPe maintained unchanged (PEEPe-S). Return of determined variable values to baseline values was confirmed before PEEPe application. ⋯ L(-1).s(-1)), and additional rs resistance (5.2 +/- 1.4 versus 7.2 +/- 1.3 cm H(2)O. L(-1).s(-1)) were reduced (P < 0.01), and hemodynamics were improved; (b) at PEEPe, PEEPi (3.7 +/- 1.3 cm H(2)O) was reduced (P < 0.01), and gas exchange was improved; and (c) at PEEPe-S, PEEPi (2.0 +/- 1.2 cm H(2)O) was minimized, and rs mechanics (static rs elastance included), hemodynamics, and gas exchange were improved. Conclusively, in carefully preselected COPD patients, bronchodilation/PEEPe exhibits additive benefits.
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Anesthesia and analgesia · Sep 2005
The suppressive effects of oxcarbazepine on mechanical and cold allodynia in a rat model of neuropathic pain.
Oxcarbazepine (OCBZ) is a keto analog of carbamazepine (CBZ) and may have similar analgesic properties to CBZ, but studies on its effects in neuropathic pain conditions are rare. In this study, we evaluated the analgesic effects of OCBZ in a rat neuropathic pain model. Male Sprague-Dawley rats were prepared by tightly ligating the left L5 and L6 spinal nerves to produce neuropathic pain. ⋯ In the OCBZ-treated groups, withdrawal frequencies to mechanical and cold stimuli were significantly reduced in a dose-dependent manner (P < 0.05). Only at the largest dose did OCBZ reduce rotarod performance time. These results suggest that OCBZ may be a possible therapeutic consideration in neuropathic pain conditions associated with allodynia and hyperalgesia.